Argon purged and sealed to be waterproof and fog proof., . External finger adjustable turret screws are easy to adjust and can be reset to zero and locked in place when not being adjusted. For use in really close range, set up the magnification low at 1x so you can use the scope with generous 4inch eye relief like a red dot sight. Mount Center Height: 30mm; Offset Length: 37mmTurret Click: 1/2 MOAParallax Setting: Free at 100yards The Hammers AR15 1-4×20 Compact Short CQB Tactical Scope is perfect for use on a 'tacticool' 22 caliber rifle as opposed to a true AR-15 Hammers 22 Rifle Scope 4X20 with Dovetail Ring Polished Silver Chrome... Sniper MK6-24x50 SAL Second Focal Plane Hunting Rifle Scope 30mm Tube Includes strong and easy to use molded rubber bikini style lens coverReticle: Glass etched 60MOA circle and 5MOA center dot at 1x illuminated in Red or Green *Reticle is visible and shows lines in black when illumination is turned offMagnification: Variable from 1x to 4xEffective Objective Diameter: 20mmExit Pupil (mm): 20@1x; 5@4xEye Relief: 4., 2inch - 3., 6inchFOV: 67-16., 8feet at 100yardsTube Diameter: 1inchObjective O., D., (mm/in): 25., 4/1 Eyepiece O., D., (mm/in): 42/1., 65Length (in): 9 5/8 Weight: 18oz. When higher reticle contrast is needed against target background, the reticle can be illuminated in in red and green light and illumination intensity in each color has five levels of adjustment to set up desired contrast. Monstrum Lpvo Lightweight Lever Action 1-4x20 Rifle Scope W/ Hog Pig Reticle Rings Speed Lever Lightweight Rifle Optic Glass etched CQB reticle features an extremely large exit pupil for low light performance and a super wide field of view at fine-tuned 1x magnification., . The scope also includes a screw-on throw speed lever that can be installed on magnification power ring for quick magnification change while keeping your eye on the target. Come with rubber molded bikini lens cover and one piece offset mount